JP3013271B2 - Pitch melt spinning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pitch for producing pitch fibers on an industrial scale from a fiber-forming pitch (hereinafter abbreviated as "pitch") made from petroleum or coal-based heavy oil. The present invention relates to a melt spinning method.

[0002]

2. Description of the Related Art At present, pitch fibers are activated carbon fibers by inactivating them after infusibilization, and are used as activated carbon fibers in the field of adsorbents such as solvents and odorous substances. It is widely used in the field of reinforcing materials as a carbon fiber.

[0003] In general, in order to spin pitch made from petroleum-based or coal-based heavy oil as a raw material, it is necessary to spin at a higher temperature than when ordinary synthetic fiber is melt-spun. Generally, the softening point of the melt-spun pitch is about 200 to 350 ° C., and is 30 ° C. lower than the softening point of the pitch to be spun during melt spinning.
As described above, the set temperature is preferably higher by 40 ° C. or more. For example, when the softening point is 290 ° C., the spinning temperature is about 340 ° C. In spinning the pitch fiber, a method of spinning a synthetic fiber has been conventionally employed as it is.

However, in the method of spinning synthetic fibers, an air supply method is employed as a cooling method during spinning, and in such a method, air is supplied from a direction perpendicular to the horizontal blowing, that is, the yarn take-off direction. As a result, yarn sway is likely to occur. In particular, when the number of discharge holes of the spinneret increases, a difference occurs in the amount of air supplied to the yarn accompanying flow at each discharge hole generated at the time of spinning, and this causes a turbulence in the accompanying flow. It appears more noticeably as the number of discharge holes in the spinneret increases. In particular, pitch has a property that yarn accompanying flow tends to occur more easily than synthetic fibers, and has a property that its softening point is high, that is, it rapidly cools and thins (solidifies) when the temperature lowers even a little. Very susceptible,
Therefore, a single yarn break of the pitch occurs due to a yarn sway in a high temperature range, or the pitch adheres to the surface of the die, impeding continuous spinnability, or a pitch fiber at the time of infusibility due to mixing of the broken single yarn. Combustion occurs, which significantly reduces operability and makes it difficult to maintain stable spinnability over a long period.Furthermore, since the pitch is composed of an aromatic condensed polycyclic compound having a wide molecular weight distribution, the During spinning, a large amount of vapor of a low-boiling substance is generated, and the vapor flows into the peripheral device together with the yarn accompanying flow, and adheres and deposits. For this reason, it is necessary to replace each device, and if the yarn is taken up by a suction gun, the change in the pulling force of the suction gun causes a change in the fiber diameter and a variation in the sheet weight per unit area. Will be reduced. In addition, since the low-boiling substance vapor itself deteriorates the working environment, it is necessary to pay close attention to the leakage of the substance to the outside.

[0005] Therefore, at present, development of a novel pitch melt spinning method which takes into account the properties unique to pitch fibers, independently of the synthetic fiber spinning method, has been desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to produce high-quality pitch fibers while improving spinning operability and environmental safety.

The inventors of the present invention have conducted intensive studies to solve the above problems, that is, the harmful effects of yarn sway and low-boiling material vapor. As a result, the yarn associated with the yarn produced during the spinning due to friction between the air and the air bundles. Flow, and that the turbulence of the air flow and the turbulence of the air, which is the source of the entrained flow, greatly affect the speed change of the yarn bundle during spinning. Elucidation of the above problems due to changes in the degree of sway of the yarn bundle due to temperature and flow direction characteristics of the air introduced into the spinning cooling chamber due to temperature dependence, and changes in the thinning point of the single yarn did. By controlling the accompanying flow generated by the friction between the fiber yarn bundle during spinning and the air based on such a viewpoint, specifically, the air flow is generated in a direction opposite to the yarn accompanying flow from the spinning cooling chamber. By supplying and uniformly supplying air to each associated flow at each discharge hole to reduce or prevent turbulence in each yarn accompanying flow, excellent spinnability is obtained and diffusion of low-boiling substances is prevented. They have found that they can do this and have completed the present invention.

That is, the present invention provides a melt-spinning having the following pitch:
Pertains to the method. 1. Manufacture pitch fibers from petroleum or coal pitch
At this time, the pressure inside the spinning cooling chamber is slightly reduced from the atmospheric pressure.
In the opposite direction to the yarn accompanying flow from the spinning cooling chamber.
Melt spinning of pitch characterized by supplying airflow
Law. 2. Combined discharge of air from yarn cooling air and spinning cooling chamber
The method for melt-spinning a pitch according to claim 1. 3. Air flow around the exhaust part of the yarn accompanying flow
The air is supplied from an air supply port installed in the section.
3. The method for melt-spinning a pitch according to item 1.

Hereinafter, the present invention will be described in detail.

First, the pitch melt spinning method of the present invention will be outlined with reference to the drawings. FIG. 1 is a schematic view showing an example of a pitch fiber sheet manufacturing apparatus. The molten pitch (P) is drawn by a suction gun (3) while being applied with a cooling fluid by a cooling device (2) immediately below the nozzle base (1) and forms a yarn (Y). The spinning cooling chamber (7) is isolated from the outside air by an isolation wall (4), and an air supply port (5) provided around the suction gun (3) is connected to a flow rate regulating valve (6). The yarn (Y) is sucked and pulled by the suction gun (3) together with the accompanying flow, and is arranged in a sheet shape by traversing the connecting portion (8) and the opening tube (9). Further, the pitch fiber sheet (S) can be obtained by a sheet forming apparatus having a guide duct (12) having an end connected to a bag filter, a suction container part (11), and a wire holding mesh (10).

The pitch that can be used in the present invention is not limited as long as its softening point is a fiber-forming one.
Preferably, the temperature is about 200 to 350 ° C. The number of discharge holes in the nozzle cap (1) is not particularly limited, and is usually about 80 to 300 per cap. The spinning temperature in this case depends on the pitch used,
Usually, it is about 250 to 400 ° C. The draft is 1
It is better to set it to about 00 to 500.

After discharge from the discharge hole, cooling is started.
The cooling fluid in the above-mentioned cooling uses various cooling fluids such as heating air or heating steam, within 150 mm immediately below the base discharge surface,
Preferably, cooling is performed from a range of 10 to 30 mm. If the cooling start position is more than 150 mm, the appropriate cooling fluid temperature region becomes narrow, and the tightness between the yarns usually occurs due to the yarn sway. On the other hand, when the diameter is less than 10 mm, unevenness in the discharge amount is caused by the influence of the temperature unevenness on the die surface, and unevenness in the fiber diameter and yarn breakage occur, so that stable spinning becomes difficult.

Next, the fluid (yarn accompanying flow (13)) discharged from the spinning cooling chamber (7) consists of a fluid to be cooled just below the surface of the spinneret and a low-boiling substance generated from the yarn. The accompanying flow rapidly increases from the solidification point and increases, and the low-boiling substance diffuses into the accompanying flow. Therefore, in order to control the accompanying flow generated without impairing the spinnability, an air flow corresponding to the flow rate of the accompanying flow is supplied to the air supply port (5) in the spinning cooling chamber in a direction opposite to the yarn bundle taking-out direction during spinning. ). In this case, the flow rate of the air supplied from the air supply port is such that it is discharged from the spinning cooling chamber by the yarn accompanying flow, and it is not preferable that the air flow is supplied by forcible pressure insertion. The reason for this is that it is desirable for the safety and health of the operator to manage the spinning cooling chamber so that the pressure is slightly reduced below the atmospheric pressure.

Further, it is preferable to discharge a larger amount of air than the yarn accompanying flow rate from the spinning cooling chamber. Therefore, the yarn drawing by the suction gun which discharges the yarn accompanying flow and the air of the spinning cooling chamber together is performed. The method of taking is suitable. However, when the yarn is taken up by a roller, it is desirable to install a suction gun in the vicinity of the yarn taking-up line and to maintain a slightly reduced pressure in the spinning cooling chamber.

In this way, the turbulence of the fluid due to the collision between the yarn accompanying flow discharged from the spinning cooling chamber and the supply air has already been reduced at the collision position, and the air supply has been stopped. Since it is arranged in the peripheral part centering on the exhaust part of the wake, there is no sudden change in temperature. Accordingly, the yarn is stable in the cooling region of the yarn, and even if the yarn sways, the yarn does not break. Further, the effect of the present invention is exerted as the number of spinning yarn spindles in a single spinning cooling chamber increases. In other words, the more the air supply port is closer to the direction perpendicular to the yarn direction, the more turbulence of the air flow near the thinning point is likely to occur, so that unless the spinning cooling space has a considerable volume, cooling spots are likely to occur. In addition, spinnability is impaired.

The yarn bundle pulled by the suction gun (3) is traversed through the opening tube (9), is formed into a sheet by a sheet forming device, and becomes a pitch fiber sheet. On the other hand, the fluid accompanying the yarn bundle is usually taken together with the yarn bundle by an air fluid such as a suction gun and is suction-induced by the sheet forming apparatus. However, if the take-up is a godet roller, the accompanying flow collection to the godet roller is performed. Guided to the duct. The guide duct is connected to a suitable separating device, for example, a bag filter, and low-boiling substances are continuously separated and captured. For this reason, the surrounding environment outside the spinning cooling chamber is not contaminated, so that the pitch can be melt-spun on an industrial scale for a long period of time.

[0017]

According to the present invention, it is possible to control the accompanying flow of yarn generated during spinning, so that stable spinnability can be achieved and diffusion of low-boiling substances can be prevented. Excellent effects on improving quality, operability and safety can be exhibited.

[0018]

The present invention will be described in more detail with reference to the following examples.

EXAMPLE 1 A coal pitch having a softening point (SP) of 280 ° C. measured by the Mettler method was set to a spinning temperature of 330 ° C. using the spinning apparatus shown in FIG. At a rate of 100 g / min and a draft 200 to produce a pitch fiber sheet. At this time, the area of the air supply port is set to 0.1 square meter, and the air supply direction is sucked through the duct so that the air supply direction is opposite to the yarn take-up direction. It was set on the peripheral surface of the gun (4), and the air supply amount was set so as to flow in about 0.3 m ³ / min by the regulating valve (6) (supply type III). Table 1 shows the evaluation results of the spinning operability and the environment around the spinning chamber.

The above evaluation method in Examples and Comparative Examples of the present invention was carried out by measuring the total number of single yarn breaks and sensory inspection of the surrounding environment while continuously spinning for 48 hours. The spinning operability was as follows: A was spinning for 48 hours and there was no single yarn breakage, B was spinning for 48 hours and no single yarn breakage occurred within 50 times, C was a single yarn breakage occurred frequently and was 48.
Shows those that did not withstand time spinning. In addition, the above-mentioned surrounding environmental conditions (environmental properties) are determined by the presence or absence of odors and low boiling substances,
0 is not recognized in both, 1 is slightly odorous, 2
Indicates that odor and outflow of low-boiling substances were observed.

Example 2 The same procedure as in Example 1 was carried out except that the spinning was performed at a discharge rate of 150 g / min per die. Table 1 shows the results.

Example 3 A coal-based pitch having a pitch softening point of 300 ° C. was used, the spinning temperature was 340 ° C., the discharge rate was 150 g / min, and the draft was 25.
The procedure was performed in the same manner as in Example 1 except that the value was set to 0. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 The direction of the air supply port was changed so that the position of the air supply port was the same as the yarn take-off direction, and the air supply port communicating with the air outside the spinning chamber through the duct was cooled (2). The procedure was performed in the same manner as in Example 1 except that the shape was directly below the circumference (supply type I). Table 1 shows the results.

Comparative Example 2 The direction of the air supply port was changed so that the position of the air supply port was perpendicular to the yarn take-off direction, and the air supply port communicating with the outside air of the spinning chamber through the duct was blown out horizontally. Supply type
Except II), it carried out similarly to the comparative example 1. Table 1 shows the results.

Comparative Example 3 The same procedure as in Comparative Example 1 was carried out except that the discharge rate was 150 g / min. Table 1 shows the results.

Comparative Example 4 The same procedure as in Comparative Example 1 was carried out except that the discharge rate was 150 g / min, the draft was 250, and the air supply direction was supply type II. Table 1 shows the results.

From the above results, it is apparent that the method of the present invention does not cause leakage of low-volatile components from the spinning cooling chamber for 48 hours, enables continuous spinning without trouble such as breakage of single yarn, and exhibits an excellent effect. is there.

Further, the pitch fiber sheet (600 g / m ² basis weight) obtained in the examples is activated and treated after infusibilization.
An average of 1550 m ² / g of activated carbon fibers was obtained by ET measurement. On the other hand, since the comparative example does not satisfy the air supply direction which is a requirement of the present invention, yarn breakage frequently occurs during spinning, making continuous spinning difficult for a long time, and low volatilization from the spinning cooling chamber. Leakage of components was observed, and the environment around the spinning room was significantly contaminated. In the case of these, partial combustion and heat debris occur when they do not melt, the processing temperature becomes unstable, and the sheets have to be excluded from the production line, which significantly impairs the operability.

[0029]

[Table 1]

From the above results, it can be seen that the pitch melt spinning method of the present invention exerts excellent effects on spinnability and the like.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a pitch fiber manufacturing apparatus of the present invention.

FIG. 2 is a view showing a concept showing a state in which supplied air flows as a yarn-associated flow in a spinning cooling chamber in a pitch fiber manufacturing apparatus of the present invention.

[Explanation of symbols]

 P ... Melting pitch Y ... Thread 1 ... Nozzle base 2 ... Cooling device 3 ... Suction gun 4 ... Isolation wall 5 ... Air supply port 6 ... Adjustment valve 7 ... Spinning cooling chamber 8 ... Connecting part 9 ... Spread tube 10 ... Sheet Holding wire net 11 ... Suction container part 12 ... Induction duct 13 ... Thread accompanying flow S ... Pitch fiber sheet

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuo Tai 1-162 Ujinojin, Uji-shi, Kyoto (72) Inventor Megumi Kibe 38 Mise-cho, Kashihara-shi, Nara Prefecture Kashihara Jingumae Sky Heights 203 (72) Inventor Yoji Sato 2-72 Nishi-Chiyogaoka, Nara-shi, Nara Prefecture (72) Inventor Yoshinori Higashi 1-145 Ujinojin, Uji-shi, Kyoto (56) References JP-A-59-168114 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) D01F 9/12-9/32

Claims (3)

(57) [Claims] In producing a pitch fiber from a petroleum or coal pitch , a pressure in a spinning cooling chamber is reduced to a pressure slightly lower than the atmospheric pressure.
A melt spinning method for a pitch, characterized in that an air flow is supplied in a direction opposite to a flow accompanying the yarn from a spinning cooling chamber while the air flow is controlled. 2. The combined yarn flow and the air in the spinning cooling chamber.
2. The method according to claim 1, wherein the pitch is discharged. 3. The air flow is centered on the exhaust portion of the yarn accompanying flow.
From an air supply port installed in the surrounding area
3. The method for melt-spinning a pitch according to 1 or 2.